Sharpeners for cutting reels

ABSTRACT

A rotatable grinding disk is supported on the frame of a cutting reel for movement in a straight line, back and forth across the knife cylinder assembly. It is also supported, in conjunction with a cover, for swinging movement into and out of operative position. There is means including a cam rod and mechanical linkages for transmitting rotary motion to the knife cylinder as the grinding stone progresses axially so that all portions of the cutting edge of an angled or helical knife are presented in proper sharpening relationship to the end face of the stone. There is also means for indexing the knife cylinder to present a new knife for sharpening after sharpening of one knife has been completed.

0 United States Patent 51 3,638,363 Witt et al. 1 Feb. 1, 1972 [54]SHARPENERS FOR CUTTING REELS 2,279,798 4/ 1942 Shelbume ..5l/48 HE [721lnventors: Wilmer E. Witt; Eugene A. Sousek; Clyde 322 et 51/249 A.Cush, a of Appleton Wis. [73] Assignee: Koehring Company, Milwaukee,Wis. Primary Examiner-William Armstrong Attorney-Morse & Morsell [22]Filed: June 15, 1970 21 Appl. No.1 46,192 [571 ABSTRACT A rotatablegrinding disk is supported on the frame of a Related Application Damcutting reel for movement in a straight line, back and forth 3Continuation f s No, 37,523 4 19 7, across the knife cylinder assembly.It is also supported, in conjunction with a cover, for swinging movementinto and out of 52 us. Cl ..s1/249, 51/48 HE Operative P There is meansincluding a cam rod and [51] Int. Cl ..B24b 19/00 mechanical linkagesu'ansmimng "Otary mmio" to the [58] Field 6: Search "51/249,246, 247,32,56, 129, knife cylinder as the grinding Progress axially that 51 I48146/1 17 1074 13 all portions of the cutting edge of an angled orhelical knife are presented in proper sharpening relationship to the endface of [56] References Cited the stone. There is also means forindexing the knife cylinder to present a new knife for sharpening aftersharpening of one UNITED STATES PATENTS knife has been completed.

2,286,970 6/1942 Maynard ..5 H48 HE 20 Claims, 15 Drawing FiguresPATNIEDFEB H972 I $638363 ama I ATTORNE S PATENTED FE I 1973 SHEUZlFlATTORNE S PAIENTED rm 11912 SBEEY 3 0f 4'- INVENTORS w v ATTORNEYSmsmium 1372 3633.363

SHEET-U 0F 4 AT TORNEYS SHARPENERS FOR CUTTING REELS This is acontinuation of application Ser. No. 687,528 filed Dec. 4, 1967.

BACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates to a sharpener for rotatable cutting reels of the typehaving angled or helical knives and is particularly suited for permanentattachment to the cutting reels of forage harvesters.

2. Description of the Prior Art To provide for the periodic sharpeningof cutting reels, particularly of forage harvesters, it has heretoforebeen suggested to perform the sharpening operation on the reel in situ,that is, without removing the individual blades or the cutting reel as awhole from the harvester. According to one suggestion which hasheretofore been made to that end, the reel housing is provided with atop opening and a sharpening stone is mounted on the reel housing sothat it can be lowered through the opening into sharpening engagementwith the reel and then moved back and forth axially of the reel from oneend to the other. The coaction of the sharpening stone with the reelblades should be such that successive sharpenings of each blade do notchange the bevel of its cutting edge. In order to accomplish this, ithas heretofore been proposed to feed a rotary grindstone along eachindividual blade, but if the blades are helical or angled, as theyusually are, provisions must then also be made to keep the cutting edgeof each helical blade in proper sharpening engagement with the rotarygrindstone as the latter is moved back and forth axially of the reel. Totake care of this past-mentioned requirement, a linkage mechanism hasheretofore been suggested which produces a partial rocking of the reelabout its axis in response to linear movement of the grindstone axiallyof the reel. Such previously suggested linkage mechanism, however, isbelieved to have not been entirely satisfactory in various respects,particularly in the matter of bringing the reel into proper rotativelyadjusted positions relative to the grindstone.

SUMMARY OF THE INVENTION Generally, it is an object of the invention toprovide an improved mechanism for sharpening the blades of a cuttingreel in situ.

More specifically, it is an object of the invention to provide animproved reel-sharpening device of the above-mentioned character whereina rotary grindstone is moved back and forth axially of the reel and thelatter is rocked slightly back and forth on its axis in response tolinear back and forth movement of the grindstone, so as to maintainproper sharpening engagement of the grindstone with helically curved orangled individual cutting blades,

A further object of the invention is to provide a sharpener asabove-described having means for automatically causing indexing of thecutter reel to bring a new knife into position after sharpening of oneof the knives of the cutting reel has been completed.

A further, more specific object of the invention is to provide asharpener wherein the grinding stone is carried directly on the end ofan electric motor shaft, and wherein the motor and grinding stone aremoved axially of the cutting reel during use, the sharpening being doneby engagement of an end face of the rotating grinding stone with theknife as the stone and motor are fed axially.

A further, more specific object of the invention is to provide asharpener in which there is cam means coupled with mechanical linkagefor transmitting partial rotation to the knife cylinder automatically asthe grinding stone is moved axially, and wherein the cam means is soshaped as to provide clearance for the right-hand tip of the knife edgeas it meets the cutter bar.

A further object of the invention is to provide a sharpener which may beinstalled as a permanent part of a cutting reel assembly, and which ismounted for quick movement into sharpening relationship when sharpeningis required.

A further object of the invention is to provide a sharpener which ismounted in a swingable frame for movement into and out of sharpeningposition, there being a cover hinged to said frame which is movable froma reel covering position, when the sharpener is on top and inactive, toan upright position during the sharpening operation.

With the above and other objects in view, the invention consists of theimproved sharpener and all of its parts and combinations, as set forthin the claims, and all equivalents thereof.

BRIEF DESCRIPTION OF THE DRAWING In the drawing, in which the samereference numerals designate the same or similar parts in all of theviews:

FIG. 1 is a perspective view looking principally from the top, showingthe improved sharpener attachment as used on a cutting reel assembly ofa forage harvester, the cover of the cutting unit being closed and thesharpener being outside of the cover so that it is inoperative forsharpening purposes;

FIG. 2 is a perspective view also looking principally from the top,showing the sharpening device in operative position for sharpening andshowing the cutting reel cover open and in a position to form a guardduring sharpening;

FIG. 3 is a fragmentary top view showing the grinding stone inengagement with one knife of the cutting reel, having moved about halfof the distance axially of the cutting reel;

FIGS. 4-9, inclusive, are partially diagrammatic views looking towardthe end of the cutting reel showing the automatic reel-rotating andknife-indexing mechanism in various progressive stages during thesharpening operation;

FIG. 10 is a fragmentary side elevational view of the sharpener carriageand motor support, the latter being shown in vertical section toillustrate adjustments for the position of the motor and cutting stone;

FIG. 11 is a fragmentary sectional view taken approximately on the line11-11 of FIG. 6;

FIG. 12 is a fragmentary perspective view looking principally from theside showing parts when the sharpening apparatus is in inactive positionon top of the cover;

FIG. 13 is a perspective view looking principally from the side andfront showing the sharpener frame swung partially upwardly and showingthe cover in suspended position;

FIG, 14 is a perspective view showing the cover swung up from thesuspended position of FIG. 13 to upright position; and

FIG. 15 is a perspective view showing the sharpener unit in operativeposition.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly toFIGS. 1-3 of the drawing, there is illustrated a cutter assembly of thetype used in forage harvesters, and including a suitable frame 20 havinga cutting reel 21 with a shaft 22 which is rotatably mounted in theframe, as is customary. The cutting reel includes a suitable spider 23supporting helical knives 24, as shown in FIG. 2, usually six in number,The invention is also applicable to straight but angled knives as shownin FIG. 3, it being understood that the mechanism shown in FIG. 3 issuitable for use with either helical or straight angled knives. Eachknife has a beveled cutting edge 25. A cover 26 is hingedly supported ina manner to be hereinafter described for movement from the closedposition shown in FIGS. 1 and 12 where it acts as a guard during use ofthe cutting reel to the open position of FIGS. 2 and 15 where it isswung to upright position when the sharpener is in operative positionfor sharpening.

A guiding tube 27 has its ends suitably secured to extensions 28 of thehead assembly (see FIG. 2). A motor-supporting carriage 29 has a tubularslide 30 connected to one of its sides which is slidably associated withthe guiding tube 27 so that the table may be slidably moved axially ofthe cutting reel, as is clear from FIG. 2. As is also clear from FIG.10, an upright motor support 31 is hinged as at 32 to the carriage 29.Any suitable means may be used to adjustably support the motor.

As one example, the upright support has a rectangular slot 33 throughwhich a lug 34 connected to the back of an electric motor 35 projects.The upper portion of the support 31 is shaped as at 36 to cradle themotor in the position shown in FIG. 10. Secured to the upper portion ofthe upright support 31 is a lug 37. A crank handle 38 has a threadedportion 39 in threaded engagement with the lug 37. Thus, when the handle38 is cranked in one direction, it will pull up on the motor lug 34 andraise the motor, and when the crank is rotated in the oppositedirection, it will lower the motor.

Pivoted to the end of the lug 37 is one end ofa clevis 40 (see FIG. 10).The other end of the clevis is closed and threaded as at 41 to receive athreaded end of an adjustment bolt 42. The latter projects upwardly atan angle from an ear 43 on the table 29 and has a head 44 on theunderside of the ear. By rotating the bolt 42 in one direction or theother, the upright motor support 31 and motor may be pivoted in onedirection or the other on the hinge 32 to adjust the angle of the motor.A locknut 45 may be employed to hold the adjustment.

The motor 35 has a depending drive shaft 46 projecting through a hole inthe carriage table and carried on the lower end of the drive shaft is agrinding stone 47, the hole in the table being large enough to permitmovement of the stone 47 therethrough. The end of the carriage tablewhich is opposite the slide 30 may have projecting studs 48 carryingrollers 49 which travel in a channel guide 50 on the frame to therebysupport and guide this end of the carriage 29 during travel of thecarriage (FIG. 1 and FIG. 12).

Projecting from the tubular slide 30 of the motor carriage 29 (see FIG.3) is a U extension 51. An endless chain 52 rotatable around sprocketwheels 53 and 54 has one of its link pins 55 projecting laterally, andone end thereof projects through and is pivoted in a vertical slot 56 ofthe bracket 51. The sprocket wheel 53 is mounted on a shaft 57 journaledin a suitable bearing 58, and the outer end of the shaft 57 carries abevel gear 59. A crank shaft 60 is suitably journaled in a bearing 61and carries on its end a bevel gear 62 which meshes with the bevel gear59. When the crank handle 63 is turned, the endless chain 52 is drivenand this will act through the projecting pin 55 to pull the motorcarriage along the tubular guide rod 27, first to the left (referring toFIG. 3), and then as the pin 55 comes to the lower stretch of theendless chain 52, it will pull the carriage back again to the right.During the movement from the upper stretch to the lower stretch, the pin55 will slide and pivot in the vertical slot 56 of the bracket 51. Forsimplicity of illustration, the crank and endless chain mechanism formoving the motor carriage has not been illustrated in FIGS. 1 and 2 butonly in FIG. 3, but it is to be un derstood that it may be employed inthe structure of FIGS. 1 and 2, or, alternatively, the sharpening unitof FIGS. I and 2 may be pushed manually back and forth.

Pivoted to the underside of the table for the carriage 29, as shown inFIG. 3, are spaced cam follower rollers 64 which coact with a curved camrod 65 constituting a control for the rocking movement. The latter hasone end pivoted to the frame as at 66 and has its other end sharplycurved as at 67 and pivoted as at 68 to one end of a link 69. Theelements 64, 65 and 69 constitute motion transmitting means. The otherend of the link 69 is pivoted as at 70 to the upper end of an actuatorarm constituting a lever or indexing element 71 which operates themechanism shown in FIGS. 4-9, inclusive, to be hereinafter described ingreater detail. It is apparent from the above that as the motor carriageis moved axially of the cutting reel, upon operation of the crank 63,the cam follower causes pivoting of the cam rod 65 on the pivot 66, withthe resultant movement of the opposite end 68, causing correspondingmovement of the link 69, which in turn transmits movement to theactuating arm 71 as dictated to by the curvature of the cam rod 65 whichprovides speed change mechanism. As before mentioned, the knife 24 shownin FIG. 3 is straight and angled. It may also be a helically disposedknife as shown in FIG. 2 and, as is common practice in cutting reels ofthe lawnmower type, there are usually six knives on a reel assembly. Asshown in FIG. 3, the motor is so supported in the upright support thatthe axis of the motor and grinding stone are tilted approximately 5toward the left (referring to FIG. 3). When the sharpening device isbeing used for sharpening, the cover 26 is in an upwardly swungposition, as shown in FIGS. 2 and 15. After sharpening has beencompleted, a latch bolt 96 is withdrawn (FIG. I) to release the cover,and the screws 106 which hold the swinging frame 101 in fixed positionare loosened.

The frame 101 has side arms 100, the inner ends of which are pivoted asat 103 so that the U-frame is swingable upwardly on the pivots 103 fromthe position of FIG. 12 to and beyond the position of FIG. 13. Thispicks up the cover 26, when the latter is on top of the reel duringoperation of the cutting reel, and causes the cover to be suspended byits hinges 104 as shown in FIG. 13. Thereafter the cover 26 is swung onsaid hinges to the upright position of FIG. 14, and the U-frame 101 isthen lowered back to a position to bring the sharpening stone into thesharpening position of FIG. 15. When in sharpening position the screws106 are again tightened to hold the U-frame rigidly to the frame of thereel unit. In addition, the bolt 105 is slid to the position shown inFIG. 15 to maintain the cover 26 in upright position and prevent itsfalling on top of the sharpening device. When in the position of FIG.15, the cover functions as a guard during the sharpening operation.

After sharpening has been completed, the screws 106 are again loosened,the bolt 105 is slid to releasing position, and the U-frame 101 is swungup on its pivots 103 to approximately the position of FIG. 13. Thispermits the cover 26 to be flipped downwardly on its hinges 104 to thesuspended position shown in FIG. 13. Thereafter the cover 26 is tuckedunder the U-frame 101, and the U-frame and cover are then lowered to theposition shown in FIGS. 1 and 12 where the cover fits over the cuttingreel to form a guard during cutting. Thereafter the bolt 96 (FIG. I) isslid to locking position to lock the cover in position, and the bolts106 are tightened to secure the U-frame 101 in its lowered position.

THE KNIFE POSITIONING AND INDEXING MECHANISM Referring now moreparticularly to FIGS. 4-9, inclusive, and FIG. 11, the actuator arm inthe form of a lever or indexing element 71 is freely pivotal around theaxis of the cutting reel shaft 22. Pivoted to the arm 71 intermediateits length" as at 72 is a knife-positioning pawl 73 having a nub 74which is shaped to fit into one of the recesses or notches 75 of a hubmember 76, the latter being keyed to the shaft 22. The elements 73-76constitute torque-transmitting elements. Linkage comprises a link 77pivotally connected at one end as at 78 to the frame and at its otherend to the outer end of a link 79. The link 79 is pivoted to theactuator arm 71 by the same pivot 72 which connects the pawl 73 to theactuator arm. An end of the link 79 which projects beyond the pivot 72carries a pivotally mounted dog 80. An upper portion of the actuator arm71 is connected by a spring 81 with a portion of the pawl 73 which is tothe right ofthe pivot 72.

Freely pivoted around the axis of the shaft 22 for the cutting reel is aknife indexing frame 82 preferably formed of spaced plates. The indexingframe has a rigid projection 83 forming a crank arm for the frame whichis connected by a spring 84 with the frame of the cutting assembly as at85. Also pivoted between the plates of the indexing frame as at 86 is aknife indexing pawl 87 having a nub 88 shaped to fit in one of thenotches 75 of the hub 76. Pivoted as at 89 to the outer side of theindexing frame is a safety arm 90. This arm is connected by a safetyspring 91 to the indexing frame 82. A pawl depressor in the form of aleaf spring 92 projects from the end of the pawl 73 between the platesof the indexing frame 82, this depressor member having a curved end 93.Also pivoted between the plates of the indexing frame 82 is a dog 94.The lower end of the safety arm is adapted to coact with a pin 95 on thedog 87.

OPERATION In use of the improved sharpening device, the cover lock 105is freed and the screws 106 are loosened. Then the U- frame for thesharpener is swung upwardly from the position of FIGS. 1 and 12, pastthe position of FIG. 13. Then the cover is swung upwardly to the uprightposition of FIG. 14 and the catch 105 is engaged to hold the cover 26 inthe upright position of FIG. 14. This permits swinging of the frame andmotor carriage down to the sharpening position of FIGS. 2 and 15. Withthe carriage at the extreme right-hand end of the cutting reel, and withthe electric motor 35 in operation, the grinding wheel 47, which iscup-shaped as shown in FIG. 10, is in engagement with the beveledcutting edge 25 of one of the blades 24, as shown in FIG. 10. The knifepositioning and indexing parts are in the position of FIG. 4. In thisposition the nub 74 of the knife-positioning dog 73 is in engagementwith one of the notches 75 of the hub, as shown in FIG. 4. As the crank63 of FIG. 3 is rotated to cause operation of the endless chain 52, thiswill move the motor and grinding wheel carriage slowly toward the left,referring to FIG. 3. As this occurs the curvature of the cam rod 65causes clockwise movement of the actuating arm 71 (referring to FIG. 4).Due to the fact that the hub 76 is keyed to the shaft 22 of the cuttingreel, as the arm 71 is swung to the right the cutting reel is partiallyrotated in a clockwise direction to compensate for the helical shape ofthe knife 24 and to always maintain the beveled portion 25 of the knifein the same relationship with the grinding stone shown in FIG. 10,regardless of the position of the grinding stone and motor in itsprogression axially of the cutting reel. Since the angle of the knivesis from right to left, clearance is needed for the right-hand tip of theknife edge (referring to FIG. 3) as it meets the cutter bar of thecutting assembly. The right-hand end of the cam rod 65 is so shaped at67 as to automatically provide this clearance in grinding, it serving toincrease the rate of angular velocity of the indexing element 71relative to the linear velocity of the carriage 29.

FIG. 5 shows the actuator arm near the end of its clockwise movementjust before the grinding stone has completed its stroke from right toleft (referring to FIG. 3). At the end of the clockwise stroke the dog80 snaps behind a shoulder 97 on the indexing frame 82. As cranking ofthe handle 63 continues, the pin 55 of FIG. 3, which connects thecarriage to the endless chain, travels down around the sprocket 54 tothe lower stretch, sliding downwardly in the slot 56. This gives adesirable time delay before the carriage reverses its direction ofmovement which occurs as cranking continues. As such cranking continuesthe carriage will now start moving toward the right (referring to FIG.3) and the shape of the cam bar 65 causes counterclockwise pivotalmovement of the actuator arm 71. Due to the engagement of the dog 80with the shoulder 97, the indexing frame 82 is now movedcounterclockwise as shown in FIG. 7. During such movement the nub 74 onthe pawl 73, which is still in engagement with one of the recesses 75 ofthe hub 76, is pushing the hub counterclockwise to reverse the reelrotation so as to still keep the beveled portion 25 of the blade inproper cutting relationship with the rotating grinding wheel 47. Duringthe movement shown in FIG. 7 the spring 84 is being stretched. Also thehooked end 93 of the depressor spring 92 is in a position engaging acorner of the pawl 87 as shown in FIG. 7. The pawl, however, cannotpivot toward the hub because the safety arm 90 has its end engaging thepin 95 to prevent such movement.

Referring now to FIG. 8, as counterclockwise movement continues the nub88 of the pawl 87 is snapped by the spring 92 into one of the recesses75 of the hub 76 as the cutting stone reaches the end of its returnstroke, the parts now being in the position shown in FIG. 9. During themovement illustrated in FIG. 8 the clevis forming the indexing frame 82moves faster because of the action provided by the linkage 77-79. Thiscauses faster rotation of the reel near the end of the stroke to pullthe 60 for indexing of the next knife.

In FIG. 9 the dog 80 flips past dead center to release the shoulder 97on the indexing frame, and this allows the turning mechanism whichincludes the spring 84 to pull on the extension arm 83 and, due to theengagement of the nub 88 of the dog 87 with the hub recess, causesrotation of the hub and reel the necessary 60 to bring another knifeinto position to be sharpened. At the end of such action the nub 88snaps out of engagement with the hub back to the position of FIG. 4.Thus the parts are again in the position to repeat the operation on thenewly indexed knife of the cutting reel. During the counterclockwiseindexing stroke, when the spring 84 is pulling on the arm 83 of theindexing frame, the dog 94 of the indexing frame is in engagement with ashoulder 96 on the right-hand end of the pawl 73, as shown in FIG. 9. Asthe indexing frame continues its clockwise movement the dog 94 snaps offof the shoulder, releasing the pawl 73 and allowing the spring 81 topivot the pawl so that its nub 74 is again engaged with a recess 75 ofthe hub, as in FIG. 4, ready for sharpening of the next knife.

From the above it is believed clear that the improved sharpener makes itpossible to efficiently employ a rotatable grinding stone with its endface engageable with the cutting edge of a blade to be sharpened, andthat all portions of the edge of the helical blade are automaticallymaintained in proper edge sharpening relationship to the stone. It isalso clear that there is means for automatically indexing the cutterreel to bring a new knife into position after sharpening of one of theknives has been completed. This latter feature, however, may beoptionally employed, and it is to be understood that the means forautomatically rocking the cutting reel as the grinding stone is fedaxially is useful whether or not there is automatic indexing of theblades from one blade to another.

It is also clear that with the present invention the improved sharpeningdevice may be a permanent part of a forage harvester or other implement,the novel swinging frame making it possible to readily shift thesharpening device into and out of operative position, there being acover which is swingable with the frame to and from reel-coveringposition.

It is to be understood that in the claims the term angled" as referringto a cutter blade means either a straight-angled blade as shown in FIG.3 or a helically angled blade as shown in FIG. 2. Various other changesand modifications may be made without departing from the spirit of theinvention, and all of such changes are contemplated as may come withinthe scope of the claims.

What we claim is:

1. In combination with a cutter assembly having a frame and having arotatably mounted cutting reel provided with angled blades, each havinga cutting edge, a sharpening stone, means including a carriagesupporting said stone on the frame for movement axially of the reel in aposition to engage and act on one of said blades thereof, a leverelement, means for releasably maintaining the reel in a predeterminedindexed relationship to said stone so that sharpening engagement of thestone with the same blade is continuously maintained as the stone movesfrom one end of a blade to the other, said last means including indexingmechanism operatively connecting said lever element to the reel, meansbetween the carriage and lever element for causing automatic partialpositive rocking movement of the reel in response to axial movement ofthe carriage, which movement is so limited in extent that the reelremains in said indexed relationship while the stone remainscontinuously in sharpening engagement with only one and the same bladeas it travels from one end of said blade to the other, said last meansincluding control mechanism between the carriage and reel-rockingmechanism whereby the rocking movement is so correlated with thecarriage movement and angle of the blade that said angled blade ismaintained in proper edge sharpening relationship with the stone as thestone is moved axially.

2. A combination as claimed in claim 1 in which the sharpening stone isrotatable and has a periphery and has end faces, and is so supported onthe carriage that one of said end faces has sharpening engagement withthe cutting edge of the blade during operation.

3. In combination with a cutter assembly having a frame and having arotatably mounted cutting reel provided with angled blades, each havinga cutting edge; a sharpening stone, means including a carriagesupporting said stone on the frame for movement axially of the reel in aposition to act on a blade thereof, reel-rocking mechanism on said frameoperatively connected to said reel for imparting positive partialrotating movement thereto, and means between said carriage andreelrocking mechanism independent of the engagement between the stoneand blade for causing positive automatic rocking movement of the reel inresponse to axial movement of the carriage so that the cutting edge ofan angled blade is maintained in proper edge sharpening relationshipwith the stone, the means for causing automatic rocking movement of thereel including cam mechanism.

4. A combination as claimed in claim 3 in which the means for causingautomatic rocking movement of the reel also includes lever mechanismbetween the cam mechanism and reel.

5. A combination as claimed in claim 3 in which said means for causingautomatic rocking movement of the reel includes a cam bar pivoted at oneend to the frame and having its other end connected to the reel-rockingmechanism, there being cam follower means on the carriage which engagessaid cam bar to cause pivotal movement of the latter as the carriage ismoved axially.

6. A combination as claimed in claim 5 in which the cam bar has a sharpcurve near said other end so that the sharpening action will provideclearance at the adjacent tip of a blade.

7. In combination with a cutter assembly having a frame and having arotatably mounted cutting reel provided with angled blades, each havinga cutting edge, a sharpening stone, means including a carriagesupporting said stone on the frame for movement axially of the reel in aposition to act on a blade thereof, means for releasably maintaining thereel in a predetermined indexed relationship with the stone forsharpening of one blade, reel-rocking mechanism on said frameoperatively connected to said reel, means between said carriage andreel-rocking mechanism for causing automatic rocking movement of thereel in response to axial movement of the carriage so that the cuttingedge of an angled blade is maintained in proper edge-sharpeningrelationship with the stone, and means between the automaticreel-rocking mechanism and the reel which is responsive to completion ofa movement of the carriage along the length ofa blade for automaticallyindexing the reel to bring another blade into position.

8. A combination as claimed in claim 1 in which the reel has a centralshaft, and in which the reel-rocking mechanism includes an arm which ismounted on said shaft and projects radially therefrom.

9. In combination with a cutter assembly having a frame, having a cutterbar, and having a rotatably mounted cutting reel provided with angledblades, each having a cutting edge with a tip at one end which requiresclearance with the cutter bar, a sharpening stone, means including acarriage supporting said stone on the frame for movement axially of thereel in a position to act on a blade thereof, reel-rocking mechanism onsaid frame operatively connected to said reel, and means between saidcarriage and reel-rocking mechanism for causing automatic rockingmovement of the reel in response to axial movement of the carriage sothat the angled blade is maintained in edge-sharpening relationship withthe stone as the stone is moving axially, said last means includingmechanism to increase the rate of velocity of rocking movement so thatsharpening will provide said clearance at said tips of the blades.

10. A combination as claimed in claim 9 in which the means between thecarriage and reel-rocking mechanism includes a cam bar extendinggenerally axially of the frame and pivoted at one end thereto and havingits other end connected to the reel-rocking mechanism, there being camfollower means on the carriage which engages said cam bar to causepivotal movement of the latter as the carriage is moved axially. saidcam bar having a sharp curve near said other end so that sharpeningaction will provide said clearance at the tips of the blades.

11. In combination with a cutter assembly having a frame and having arotatably mounted cutting reel with a shaft and provided with spacedblades, each having a cutting edge, a sharpening stone, means includinga carriage supporting said stone on the frame for movement axially ofthe reel in a position to act on a blade thereof, means for releasablymaintaining the reel in a predetermined indexed relationship with thestone for sharpening of one blade, and means responsive to completion ofmovement of the carriage along the length of a blade for automaticallyindexing the reel to bring another blade into position.

12. In combination with a cutter assembly having a frame and having arotatably mounted cutting reel provided with blades, each having acutting edge, a sharpening stone, means including a carriage supportingsaid stone on the frame for movement axially of the reel in a positionto act on a blade thereof, and means between the carriage and reelresponsive to return of the carriage to starting position after movingback and forth along one blade for automatically indexing the reel tobring another blade into position.

13. A combination as claimed in claim 12 in which the automatic indexingmeans includes ratchet and dog mechanism between said reel shaft andframe.

14. A combination as claimed in claim 1 in which the means forsupporting the carriage includes an auxiliary frame pivotally connectedto the cutter'assembly in a position to move the sharpening stone intoand out of operative position.

15. in combination with a cutter assembly having a frame and having arotatably mounted cutting reel provided with angled blades, each havinga cutting edge, a sharpening stone, means including a carriagesupporting said stone on the frame for movement axially of the reel in aposition to act on a blade thereof, reel-rocking mechanism on said frameoperatively connected to said reel for imparting positive partialrotating movement thereto, and means between said carriage andreelrocking mechanism independent of the engagement between the stoneand blade for causing positive automatic rocking movement of the reel inresponse to axial movement of the carriage so that the cutting edge ofan angled blade is maintained in proper edge-sharpening relationship tothe stohe, the means for supporting the carriage including an auxiliaryframe pivotally connected to the cutter assembly frame in a position tomove the sharpening stone into and out of operative position, in whichthere is a cover hinged to the auxiliary frame for swingable movement toand from a position beneath the auxiliary frame and over the cuttingreel, said cover also being mounted for swinging movement to an uprightposition in front of the sharpening stone when the sharpening stone isbeing used, and means for supporting the cover in said upright position.

16. In a sharpening device for a cutting reel which is rotatably mountedin a housing and has a number of circumferentially spaced angled cuttingblades, the combination of a carriage guided on said housing for backand forth movement axially of said reel, a grindstone mounted on saidcarriage for back and forth movement therewith, an indexing elementpivotally mounted on said housing, motion transmitting means responsiveto said back and forth movement of said carriage to swing said indexingelement back and forth on its pivot center relative to said housing, andreleasably interconnected torque transmitting elements secured to saidreel and indexing element and operable to selectively determinerotatively adjusted positions of said reel in which said blades arepresented, respectively, in edge-sharpening relation to said grindstone17. A sharpening device as set forth in claim 16 wherein said torquetransmitting elements comprise a circumferentially notched hub securedto said reel, and a pawl element connected to said indexing element andselectively engageable with any one of a plurality of notches of saidhub.

said indexing element into one of its end positions to automaticallyrelease said reel from said indexing element.

20. A sharpening device as set forth in claim 19 and further comprisinga turning mechanism for said reel responsive to release of said reelfrom said indexing element to move another of said blades intoedge-sharpening relationship with said grindstone.

l l t

1. In combination with a cutter assembly having a frame and having arotatably mounted cutting reel provided with angled blades, each havinga cutting edge, a sharpening stone, means including a carriagesupporting said stone on the frame for movement axially of the reel in aposition to engage and act on one of said blades thereof, a leverelement, means for releasably maintaining the reel in a predeterminedindexed relationship to said stone so that sharpening engagement of thestone with the same blade is continuously maintained as the stone movesfrom one end of a blade to the other, said last means including indexingmechanism operatively connecting said lever element to the reel, meansbetween the carriage and lever element for causing automatic partialpositive rocking movement of the reel in response to axial movement ofthe carriage, which movement is so limited in extent that the reelremains in said indexed relationship while the stone remainscontinuously in sharpening engagement with only one and the same bladeas it travels from one end of said blade to the other, said last meansincluding control mechanism between the carriage and reel-rockingmechanism whereby the rocking movement is so correlated with thecarriage movement and angle of the blade that said angled blade ismaintained in proper edge sharpening relationship with the stone as thestone is moved axially.
 2. A combination as claimed in claim 1 in whichthe sharpening stone is rotatable and has a periphery and has end faces,and is so supported on the carriage that one of said end faces hassharpening engagement with the cutting edge of the blade duringoperation.
 3. In combination with a cutter assembly having a frame andhaving a rotatably mounted cutting reel provided with angled blades,each having a cutting edge; a sharpening stone, means including acarriage supporting said stone on the frame for movement axially of thereel in a position to act on a blade thereof, reel-rocking mechanism onsaid frame operatively connected to said reel for imparting positivepartial rotating movement thereto, and means between said carriage andreel-rocking mechanism independent of the engagement between the stoneand blade for causing positive automatic rocking movement of the reel inresponse to axial movement of the carriage so that the cutting edge ofan angled blade is maintained in proper edge sharpening relationshipwith the stone, the means for causing automatic rocking movement of thereel including cam mechanism.
 4. A combination as claimed in claim 3 inwhich the means for causing automatic rocking movement of the reel alsoincludes lever mechanism between the cam mechanism and reel.
 5. Acombination as claimed in claim 3 in which said means for causingautomatic rocking movement of the reel includes a cam bar pivoted at oneend to the frame and having its other end connected to the reel-rockingmechanism, there being cam follower means on the carriage which engagessaid cam bar to cause pivotal movement of the latter as the cArriage ismoved axially.
 6. A combination as claimed in claim 5 in which the cambar has a sharp curve near said other end so that the sharpening actionwill provide clearance at the adjacent tip of a blade.
 7. In combinationwith a cutter assembly having a frame and having a rotatably mountedcutting reel provided with angled blades, each having a cutting edge, asharpening stone, means including a carriage supporting said stone onthe frame for movement axially of the reel in a position to act on ablade thereof, means for releasably maintaining the reel in apredetermined indexed relationship with the stone for sharpening of oneblade, reel-rocking mechanism on said frame operatively connected tosaid reel, means between said carriage and reel-rocking mechanism forcausing automatic rocking movement of the reel in response to axialmovement of the carriage so that the cutting edge of an angled blade ismaintained in proper edge-sharpening relationship with the stone, andmeans between the automatic reel-rocking mechanism and the reel which isresponsive to completion of a movement of the carriage along the lengthof a blade for automatically indexing the reel to bring another bladeinto position.
 8. A combination as claimed in claim 1 in which the reelhas a central shaft, and in which the reel-rocking mechanism includes anarm which is mounted on said shaft and projects radially therefrom. 9.In combination with a cutter assembly having a frame, having a cutterbar, and having a rotatably mounted cutting reel provided with angledblades, each having a cutting edge with a tip at one end which requiresclearance with the cutter bar, a sharpening stone, means including acarriage supporting said stone on the frame for movement axially of thereel in a position to act on a blade thereof, reel-rocking mechanism onsaid frame operatively connected to said reel, and means between saidcarriage and reel-rocking mechanism for causing automatic rockingmovement of the reel in response to axial movement of the carriage sothat the angled blade is maintained in edge-sharpening relationship withthe stone as the stone is moving axially, said last means includingmechanism to increase the rate of velocity of rocking movement so thatsharpening will provide said clearance at said tips of the blades.
 10. Acombination as claimed in claim 9 in which the means between thecarriage and reel-rocking mechanism includes a cam bar extendinggenerally axially of the frame and pivoted at one end thereto and havingits other end connected to the reel-rocking mechanism, there being camfollower means on the carriage which engages said cam bar to causepivotal movement of the latter as the carriage is moved axially, saidcam bar having a sharp curve near said other end so that sharpeningaction will provide said clearance at the tips of the blades.
 11. Incombination with a cutter assembly having a frame and having a rotatablymounted cutting reel with a shaft and provided with spaced blades, eachhaving a cutting edge, a sharpening stone, means including a carriagesupporting said stone on the frame for movement axially of the reel in aposition to act on a blade thereof, means for releasably maintaining thereel in a predetermined indexed relationship with the stone forsharpening of one blade, and means responsive to completion of movementof the carriage along the length of a blade for automatically indexingthe reel to bring another blade into position.
 12. In combination with acutter assembly having a frame and having a rotatably mounted cuttingreel provided with blades, each having a cutting edge, a sharpeningstone, means including a carriage supporting said stone on the frame formovement axially of the reel in a position to act on a blade thereof,and means between the carriage and reel responsive to return of thecarriage to starting position after moving back and forth along oneblade for automatically indexing the reel to bring another blade intoposition.
 13. A combination as claimed in claim 12 in which theautomatic indexing means includes ratchet and dog mechanism between saidreel shaft and frame.
 14. A combination as claimed in claim 1 in whichthe means for supporting the carriage includes an auxiliary framepivotally connected to the cutter assembly in a position to move thesharpening stone into and out of operative position.
 15. In combinationwith a cutter assembly having a frame and having a rotatably mountedcutting reel provided with angled blades, each having a cutting edge, asharpening stone, means including a carriage supporting said stone onthe frame for movement axially of the reel in a position to act on ablade thereof, reel-rocking mechanism on said frame operativelyconnected to said reel for imparting positive partial rotating movementthereto, and means between said carriage and reel-rocking mechanismindependent of the engagement between the stone and blade for causingpositive automatic rocking movement of the reel in response to axialmovement of the carriage so that the cutting edge of an angled blade ismaintained in proper edge-sharpening relationship to the stone, themeans for supporting the carriage including an auxiliary frame pivotallyconnected to the cutter assembly frame in a position to move thesharpening stone into and out of operative position, in which there is acover hinged to the auxiliary frame for swingable movement to and from aposition beneath the auxiliary frame and over the cutting reel, saidcover also being mounted for swinging movement to an upright position infront of the sharpening stone when the sharpening stone is being used,and means for supporting the cover in said upright position.
 16. In asharpening device for a cutting reel which is rotatably mounted in ahousing and has a number of circumferentially spaced angled cuttingblades, the combination of a carriage guided on said housing for backand forth movement axially of said reel, a grindstone mounted on saidcarriage for back and forth movement therewith, an indexing elementpivotally mounted on said housing, motion transmitting means responsiveto said back and forth movement of said carriage to swing said indexingelement back and forth on its pivot center relative to said housing, andreleasably interconnected torque transmitting elements secured to saidreel and indexing element and operable to selectively determinerotatively adjusted positions of said reel in which said blades arepresented, respectively, in edge-sharpening relation to said grindstone17. A sharpening device as set forth in claim 16 wherein said torquetransmitting elements comprise a circumferentially notched hub securedto said reel, and a pawl element connected to said indexing element andselectively engageable with any one of a plurality of notches of saidhub.
 18. A sharpening device as set forth in claim 16 wherein saidmotion transmitting means includes a speed change mechanism responsiveto movement of said carriage toward one end of said reel to increase therate of angular velocity of said indexing element relative to the linearvelocity of said carriage.
 19. A sharpening device as set forth in claim16 and further comprising a mechanism responsive to swinging movement ofsaid indexing element into one of its end positions to automaticallyrelease said reel from said indexing element.
 20. A sharpening device asset forth in claim 19 and further comprising a turning mechanism forsaid reel responsive to release of said reel from said indexing elementto move another of said blades into edge-sharpening relationship withsaid grindstone.